Drying apparatus



July 5, 1938. E.J. SWEETLAND L f DRYING APPARATUS Filed March 27. 1934 Fig.2. I

Patented July 5, 1938 UNITED STATES.

PATENT OFFICE This invention relates to a drying apparatus and particularly to apparatus adapted for drying plaster casts as they are applied to the human body for surgical purposes. It is common practice to applyplaster casts to the human body to hold parts thereof in place during the knitting of broken bones and for other purposes. Frequently such casts, in cases of broken backs, broken hips and the like, are large enough to enclose the major portion of the trunk and lower limbs of the body. In such instances the question of drying the cast is a serious one for several reasons. Patients frequently contract pneumonia from long continued contact with the wet plaster cast. Not only are such casts extremely uncomfortable while they are wet but the coolness produced by evaporation tends to reduce body temperature at a time when the patients resistance is low due to shock, loss of blood, etc. 29 and it is therefore important to warm and dry the entire cast with the least possible delay after it is applied. Another difliculty that is commonly encountered is that the cast does not attain its full strength until it is substantially dry and they 2 are frequently broken while the patient is being moved in the wet cast.

The customary method for drying plaster casts at present in use is by means oi electric lamps and 1 similar heating devices which are brought in prox 80 imity with a portion of the cast at a time.

methods are unscientific and unsatisfactory because extreme vigilance is necessary to avoid allowing the cast to become overheated in spots, thus causing discomfort or actual injury to the 36 patient. Furthermore, such methods necessitate drying only a portion of the cast at a time, under which circumstances it is impossible to make the patient comfortably warm at all parts of the body, and it has the further objection that the 40 patient must be moved to several diflerent positions before complete drying can be effected. Moving and turning the patient over under these circumstances frequently causes great pain and actual danger of increasing his injury.

45 The object of my invention is to provide a method and apparatus for drying plaster casts promptly and uniformly without danger to the patient and without the necessity of moving the patients body during the entire drying operation.

50 My method requireslfrom two to flve hours for complete and satisfactory drying whereas the methods at present in use usuallyrequire from 24 to 48 hours to attain the same degree of dryness.

55 A further object of the invention is'to provide Such uniform means of increasing the body temperature. Also I provide means for quickly reducing the temperature it required for the patients comfort.

To accomplish the objects of my invention I 5 employ a eertain'apparatus illustrated in detail in the accompanying drawing.

Referring to the drawing: Figure 1 represents an elevation partially in section showing the apparatus in operation. 10

Figure 2 is a fragmentary sectional view take on the lines 1I1I of Figure 1.

Figure 3 is a plan'view showing a portion of the apparatus in section.

Figure 4 is asectional elevation of one of the 15 nozzles showing means of securing the nozzles in operative position. 1

Figure 5 shows a modification of my invention wherein felt spacing members may be used in certain cases as a substitute for the wire mat.

Figure 6 is a modification wherein a sheet is secured to each side of the metallic mat.

Referring to the drawing in'detail, i indicates a bed uponwhich is mounted the customary mattress and springs 3. 4 diagrammatically indi- 2 cates a cross section of the human body which is surrounded by the plaster cast 5. Surrounding the cast 5 is the coiled spring mat 6 and this in turn is surrounded by the sheet I, which sheet is reinforced longitudinally by a plurality of stays 8 which-are held-in. place by rows of stitching which form pockets between the two layers of fabric of which the sheet 1 is composed. The stays l are preferably made of stainless spring steel, although they may be made of thin strips of wood or any suitable material which tends to stiffen the sheet longitudinally while permitting lateral flexibility. These stays are of thin spring material which permits a reasonable amount of longitudinal flexibility so that the sheet may conform to the indentations formed in the mattress by the contour of the body. The sheet I may be of canvas or any flexible material which does not permit air to pass through it freely. I is a nozzle which is flattened at its delivery end so as to distribute the air stream delivered through the tubes Ii. I0 is a loose plate of sheet metal which may be used to direct thestreams of air and prevent them from being dissipated before they are well started through the channels of the mat. If desired to reverse the flow of air currents so that they enter at the top of the cast and discharge from the bottom side, this plate is then inserted between the springs 6 and the top of the cast and the position of the nozzles changed accordingly.

i .which is made of resistance wire and is heated by an electric current which is supplied through the cables l6, l1 and IS. The circuit through the heating element as well as the motor in the casing I3 are controlled by the switch IS. The cable 2| is assumed to be a double cable and the switch IS a double switch which simultaneously turns the current on in the motor and heating element. Adjacent to theheating element is the device 22 which may be either a rheostat or an ordinary switch for regulating the current in the heating element. If a rheostat is used the temperature of the-discharged air may be regulated to any desired degree. 23 is "a thermostatic element which is located in the top of the blower housing and is connected by conduit 24 to the thermostatic switch 25, the object of which isto automatically cut off the current flowing through the heating element in case the temperature should exceed a pie-determined point, say 120 F. As the thermostatic element and switch are well known standard equipment, detailed description is not deemed necessary. The stand 26 supports the entire unit and is preferably mounted on the rollers 21. Current for the unit is supplied through cable 28 which may be plugged into any convenient receptacle such as 28.

The mat 8 is preferably made of a plurality oi coiled springs which are interlocked to hold them in position and I prefer to make the springs from i to 1%; inches in diameter and with wire of such size as provides suiificient strength to sustain the required weight and provide the desired resiliency.

Figure 2 is a fragmentary view showing some of the helical springs of the met as seen along the line of the axis of said springs and the method by which they are interlocked. As indicated, each turn of wire engages an adjacent turn oi the neighboring coil. A portion of the sheet I and section oi the plaster cast 5 are indicated in this view.

The tubes il are preferably made of light material supported by an internal coiled spring to prevent them from kinking or collapsing. The

middle tube 1 i is provided with an extended sleeve 3| which telescopes through the collar 32 to provide a certain degree of adjustment in length to compensate for the various curves that may be made in the outer tubes when they are spread at various distances apart. Any number of tubes ii and nozzles 9 may be used to carry out the principles of my invention, depending upon the size and requirements of the apparatus.

Reierring to Figure 3 the coiled spring mat 6 is shown in plan view, no client being made to illustrate the body or the patient in this view. Plate I0 is omitted in this figure. In Figure 3 the sheet 1 is partly broken away to show the spring matand position of the nozzles. This view also illustrates my method of preventing escape of the air currents through the edges of the mat. This is accomplished by threading a round strip of felt or wadding of any "kind through the outer coil of the mat as indicated by the numeral 33. If

it is desired to use only a portion of the mat in cases where the cast may be'shorter than the mat,

the strip of wedding 33 may be threaded through any coil in the mat thus forming an eifective dam which confines the air currentsto the desired area, thus forcing them to circulate entirely around the body of the cast as indicated by the arrows in Figure 1. In Figure 3 the area indicated by the numeral 34 has one layer of the fabric of which the sheet is made removed to show the position of the stays 8 which are held in place by the stitching 31. 7

Referring to Figure 4 a section of the tube II is broken away to show the coiled spring I. and connection to the nozzle 9 and this view shows an enlarged view of the catch 39 which helps to hold the nozzles in operative position. This catch consists of a shank 4| which passes through openings in the angle pieces 42 and terminates in hook 43. A helical compression spring 44 bears againstthe collar 45 which is fixed to the shank 4i and urges the shank towards its upward position as shown. When desired to remove the nozzle the latch 39 is pushed downwardly to disengage the hook 43 from the spring 6 so that the nozzle may be changed in its position or removed entirely.

Figure 5 is a modified form of my invention in which the numeral 45 indicates a layer of canvas or other suitable fabric to which is secured by any convenient means, such as stitching or cement, a plurality oi strips of felt I. In this View the numerals 41 indicate nozzles through which warm air is discharged and the numeral L-a represents a section of a plaster cast. In this figure the felt strips form the spacing element for which wire mat is used in Figures 1 and 3. In this modification the canvas and felt strips assembled together as shown constitute the mat.

When this modification is used the canvas sheet is made sumciently large to surround the cast and is placed so that the felt strips and the canvas form channels encircling the cast, and through which the warm air currents are conducted.

The modification shown in Figure 6 has the mat 6 and sheet i the same as shown in other views; but in this case another sheet la- (preferably without stays) is placed on the upper side of the mat and the whole is held together by basting them at intervals with a heavy thread lb.

It should be understood that the mat i and the sheet I are preferably secured together at least at the outer edges, as for instance, by occasional stitches as indicated by the numeral bi, as this enables the sheet with its stays I to maintain the mat always in a straight, convenient position for operation. However, these two parts may be separate units if desired.

The modus operandi is as follows: The mat and its attendant sheet are spread on the bed with the mat 5 upward and the patient is then laid on the mat with the mat preferably extending throughout the entire length of the plaster cast. The nozzles are then latched into position as indicated in Figures 1, 3 and 4 and the mat and sheet are folded back over. the patient to the position indicated in Figure 1. The switch II is then turned on and this simultaneously starts the motor and blower in operation and turns the current through the heating elements I. This starts a blast of warm air discharging through. all of the nozzles, creating warm air currents which are somewhat diffused within the spaces of the mat and these encircle the patient and discharge from under the sheet carrying with them moisture which is rapidly evaporated from the cast.

The nozzles, aswill be noted from the drawing, do not need to cover the entire open end of Bill the lower side of the mat butto promote even- 15 ness and rapidity in drying, the position of the nozzles may be changed from time to time;

conform nicely to-the shape 'ofthe plaster oast for they cooperate with the springs 01' the bed which compress more in some places .thanin 1-. An apparatus for drying plaster casts on v the human body comprising a flexible mat made It will be seen that theflexible mat and sheet others, so that they maintain a perfect contact. a oi the mat with the plaster cast on the lower sidei n the upper side good contact is easily arranged by the attendant who carefully places the mat to conforrn'to the shape of the cast. Thus it will be seen that the entire cast is dried simultaneously and without the necessity of moving the patlent at all. The thermostatic element and a switch 23 and 2! automatically cut oil the current in the heater in the event that it should tend to become too hot for the-comfort of the patient. This some action ,can be accomplished manually by means of switcher rhesostat 22 it til desired. In fact i! the patient becomes uncomfortably warm the cool air which is forced through the mat when the current is turned ofl afl'ordsan excellent method of reducing the temperature in a very short time.

If desired, the same apparatus may be used either tor warming or cooling a patient even in cam where a plaster cast is. not involved, and it is within the spirit of the invention to so employ the apparatus for special therapeutic purposes. The modification shown in Figure 6 is especially adapted for this purpose, the mat, covered by a sheet on loath sides being wrapped around the patient and air currents of the desired temperature are blown through the channels in the some manner as used for drying costs.

The apparatus herein described provides ideal human body comprising a flexible met consist- 85 conditions for rapidly drying plaster casts in that it supplies warmth and rapid means of carrying away the moist vapor and bringing fresh air in contoct with the surfaces oi the cast.

ll extreme speed is essential desiccated air may he led to the blower intake, hut this is not ordinarily nmssary.

While I have shown only the simplest form of sheet and wet it should he understood thatvarions shapes may be used, such for instance as tubular ones to fit over the limbs.

Where the term sheet is used in thefollowlne claims it is intended to in one or more layers oi iahric or other terlal capable of forming a fleidhle wall to retain and guide the air currents in proper location to perform the functions described and it may or may not be supplied with stays or other stiflening means.

where the terms ces or plaster castmay he used in the following cl it is intended to e a body of plaster of Paris or similar material used for supporting the limbs or other parts of the body after the setting of bones and for other surgical purposes. The plaster may or may not be reinforced hy ialorlc or other material. A These devices are referred to by some physicians as plaster cases. 7

or a series 0! coiled springs having open spaces to permit tree circulation of air currents, a sheet offlexible materlal substantially impervious to fair currents on one side of said mat, conduit meats for leading air currents from a blowing apparatus to the open spaces in said mat.

2. An apparatus for drying casts on the human body comprising a flexible mat'consisting of a 10 plurality of open interlocked resilient wire Q18? ments capable of supporting the body and cast wlthout collapse and adapted to surround the body and cast with one open side oi the mat directly contacting the cast, a flexible cover and deflector for the otherslde of the mat adapted to envelop the mat and cast, a-blower for circulating a stream at air, heating means for warming the air stream circulated by the blower,

and means for conducting the heated air stream 20 from the blower into the mat in a dirmtion substantially tangential to the surface of a cast.

3. A warmingand drying apparatus comprismg a flexible mat constructed of a plurality oi coiled springs interlocked together with the axes the convolutions of said springs;' air warming means associated with said blowing means: conduit means to convey the air from said blowing means to said passageways.

4i. An apparatus for drying plaster costs on the ing of interlocked coil elements with open spaces for free circulation of air currents throughout the mat, said mat having its edges free and fienihle and said interlocked elements being normally free from tension; the wire elements on one side to of said mat coroprisina supporting nienihers for direct contact with said plaster cmt and providing open communication for so of air iirom the mat to the surface oi said cast; a domicile deflecting cover on the other side of the met, as

interlocked metallic members forming a flexible till 1 met capable of supporting the body and cast without collapse, and having substantially unrestricted passageways for air to allow difiuslon of an air stream throughout the mat in direct contact with the body and cast, forcing a stream to of air into the mat for difiusion therewlthin,

controlling the temperature of the air stream, and confining the air stream in ago through the mat and in contact with the body and cast by a flexible cover and deflector applied to the to V side of the mat opposite that in contact with the body and cast.

6. The method'of drying casts on a human body which comprises supporting the and cast in spaced relationship to the reclining r face of a bedon one side of and in dl t con-- tact with a flexible mat of open interlocked wire elements having substantially unrestricted" passageway for air to allow diduslon of an air stream throughout the mat and in contact with the 76 Kill and cast, covering the other side of the mat with a flexible cover and deflector and forcing a stream of air into the edge of the mat for diffusion therewithin and in contact with said cast, and modify ing the temperature oi the air stream in its passage to the mat.

l. The method of drying casts on a human body which comprises supporting the body and cast in spaced relationship to the reclining surface of a bed on one side of and in direct contact with a flexible mat of open interlocked wire elements having substantially unrestricted passageway for air to allow diffusion of ariair stream throughout the matand in contact with the body and cast, directing a forced air stream underneath said cast and deflecting said current of air around the cast ina direction substantially parallel with the surface of said cast; whereby the air stream is caused to circulate substantially around the entire cast to accelerate evaporation from the surface of the cast.

3. Means for circulating air currents underneath the body or a person in bed which comprises a flexible wire mat capable of sustaining the weight of said person without collapse; said mat being formed of a plurality of symmetrical blower means to project air currents into said air passageways and a heating element for warming the air "currents projected by said blower; a conduit to lead said air currents from said blower to said mat; said conduit being exterior to and independent of said mat and terminating in a dispersing flared nozzle with its opening directed toward the passageways in said mat whereby said air currents are immediately dispersed upon being discharged into said passageways for free and unrestricted circulation throughout the entire'boundaries of said mat.

9. Means for circulating air currents underneath the body of a person in bed which comprises a. flexible mat capable of sustaining the body of said person without collapse; said mat being formed of a plurality of helically coiled interlocked metallic elements; the spaces within blowing air currents into all of said passageways;

means for warming said air currents; conduit means for conducting said air currents from said blower means to said mat; said conduit terminating in a flared dispersing nozzle adjacent the edge of said mat for discharging said air currents into said mat and causing them to disperse throughout said interconnecting passageways whereby warm air is diffused underneath the body of said person.

ERNEST J. SWEETLAND. 

